Mobile communication systems were developed to provide the subscribers with voice communication services on the move. With the rapid advance of technologies, the mobile communication systems have evolved to support high speed data communication services beyond the early voice-oriented services.
Until now, the development of wireless communication systems have been focused on Point-To-Point (PTP) communication mode. Here, the term “point” denotes calling party (or called party) in a case when two users (calling and called parties) are communicating each other). In an exemplary situation when a user attempts accessing a website, e.g. http://www.amazon.com/, the two points are the user and the amazon server respectively.
Recently, the interest about group communication service through a wireless communication system increases. Group communication is a general term used to describe communication among multiple participants such as broadcast.
The group communication service may be provided through the legacy PTP communication scheme. In the broadcast example, a broadcast provider provides communication paths established between the broadcast provider and a plurality of users interested in the broadcast. However, this method is very inefficient in view of resource utilization. In an exemplary case where a plurality of users request for the same or similar data, transmitting the common data to the plural users through the user-specific PTP paths repeatedly results in significant resource utilization inefficient.
There is therefore a need of a Point-To-Multipoint (PTM) mode for group communication service that is capable of utilizing resource efficiently. For PTM mode communication, Long Term Evolution (LTE) adopts Multimedia Multicast Broadcast Service (MBMS). The issue about providing a group communication service through MBMS is discussed actively in the 3rd Generation Partnership Project (3GPP).